Nostr Web Client

https://video.nostr.build/fe40f309c4458fc0ee83f70cdaa1403703fee22882de409362cf74422d9934f6.mov

As promised, I solved the List Synchronization Problem (your contact list being swiped out problem) for the whole Nostr community so that you don't have to re-invent the algorithm again.

Here is a demonstration with Relay List, which is a harder version of the problem because we also use relays to synchronize the configuration of themselves.

You can open 2 different devices/clients and modify the same list with different values, and they will converge to the same value instead of overriding each other.

Watch what happened from 26s - 28s!

The secret is using a data structure of CRDT. More on this later.

I'm just tagging more nostr developers I have on top of my head. Feel free to tag & share to other developers & users.

Feedbacks welcome. If the effect in the video is what you consider a solution for the list synchronization problem and upvote this note, I will draft a NIP.

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Discussion

hodlbod 2y ago

Yes, I'm interested in this, what CRDT did you use? Definitely draft a nip, more robust list building is applicable in many places.

Water Blower 2y ago

At first I wrote my own, ignorant, didn’t work.

Now it’s Automerge. It has Rust implementation and wasm for JS and the API is simple. Technically the rust implementation can be used everywhere.

Water Blower 2y ago

Yjs and Yrs should also work but it doesn’t have a good Deno support so I didn’t use.

Water Blower 2y ago

But one thing I noticed was that parameterized replaceable events were much slower to query comparing to normal events. Maybe strfry isn’t optimized for it yet. Need to test with more relay implementations.

nym 2y ago

Clever!

hzrd149 2y ago

This looks cool, but I have a few questions.

In the example you showed each client is creating a different relay list, then when it discovers a relay list created by the other client it merges it.

1. How dose this handle removing different relays in both clients. wouldn't the client just see the relay list from the other client and add the recently removed relay back into the list?

2. Due to how events are spread between relays, A lot of the more obscure relays have really old versions of my relay list. If the app happened to connect to a relay that had a 2+ day old version of my relay list would it attempt to merge it with the newest relay list, even though there are relays that I explicitly wanted to remove?

I like the idea of detecting and merging the relay list. but if it defaults to always merging whatever lists it finds. then I think this could make it difficult to remove relays.

Water Blower 2y ago

Good questions! Here is a video about removals.

I have 2 browsers open, computer offline.

The left removes nos.lol and the right adds nostr.wine.

Then computer goes online,

the left gets nostr.wine added and the right gets nos.lol removed.

They both converge to the same result list/set no matter how much remove/add you do.

Operations can happen out of order, very old, offline, doesn't matter.

Does this address your concern?

https://video.nostr.build/94209ea5ea637e3c3bd28e1d8063b7b095f2faefa71ca6d03399906786ab05d9.mov

Water Blower 2y ago

nostr:npub1xtscya34g58tk0z605fvr788k263gsu6cy9x0mhnm87echrgufzsevkk5s This video is clipped.

Silence 2y ago

CRDT - Conflict-free Replicated Data Type

CRDTs ensure that, no matter what data modifications are made on different replicas, the data can always be merged into a consistent state.

https://crdt.tech/